Field of the Invention
This invention relates to an electrical converter of the type, (hereinafter referred to as being the kind specified), for supplying electrical power to a load from a d.c. source and which includes semi-conductor switching means for converting a direct input current to an alternating current, and output transformer means fed with the alternating current for changing the magnitude of the output voltage with respect to the input voltage.
Such semi-conductor switching means in conventional circuits of the kind specified typically comprises transistors which have higher gains than are strictly necessary, in order to ensure that each such transistor can switch fully on (i.e. saturate) when required to do so even when provided with weak input voltages. Compared with lower gain transistors, such high gain transistors are relatively expensive, have relatively long storage times which both limit the frequency of said alternating current and introduce phase lags which cause switching losses to occur, and carry on undesirably high main current when supplied with a higher than average input signal, thus giving rise to unwanted heating effects.